Flotation apparatus



UNITED STATES ILKJENT oFncE.

WILLIAM E. GREENAWALT, OF DENVER, COLORADO.

FLOTATION APIABATUS.

Specification of Letters Patent. Patented Apr. 12, 1921.

' Application filed May 26, 1916, Serial No. 100,001. Renewed March 22, 1920. Serial ,No. 367,829.

" T 0 all whom it may concern:

WILLIAM E. GREENA',

Be it known that I, wAL'r,a citizen of the Umted States, residing in the city and county of Denver and 5 State of Colorado, have invented certain 10 tus, and has for its object the effective separation of minerals from their gangue introducing -a gas into the flotation liquid and atomizing the gas in the l1qu1d. It 1s not intended, however, tolim'it the apparatus to this use alone. i

The gas, introduced into the l1qu1d, is brought into a fine state of sub-dl'vlsion by means of rapidly rotating perforated disks in its ascent through the liquid, and the atomized gas, rising to the surface, effectively floatsthe fioatable mineral part1- cles in the presence of a frothing agent,

This method of applying the gas 1s par.- ticularly effective in flotation operatlons. It

is most effective when the gas bubbles are. "brought into a very mlnute state ofsubdivision, and it is best accomplished when the relative motion between the liquid and atomizer of the gas is as great as possible. In the present application the best efiect 1s obtained when the perforated disks. rotate at a comparatively high speed while the liquid remainszcomparat-ively stationary or 'quiescent. It is also desirable to have the surface ofthe liquid as quiescent as possible, under the conditions, so that the mineral froth may be floated more effectively and 'a.

high grade of flotation concentrate obtained. The apparatus can best be described by referring to the accompanying drawings, 1n which Figure 1, represents a vertical secv tionthrough the apparatus; Fig. 2', a hori-' ZO'iltfll section on'the line' 2 2, Fig. 1, on a reduced scale; Fig. 3, a-horizontal section on the line 33, Fig. '1, on a reduced scale; and Fig. 4, a' detail of the perforated-plates.

In the drawings,v 1 represents a .tank

adapted to contain a liquid and the material tobe" treated. 2 represents perforated disks, 5.0 suspended within the tank and submerged in the'liquid, andhaving perforations 2 throughwhich gases may passin their as .cent through the liquid whenin troduced- .into the tank 1. 3 represents plates; inter- 5 posed between the disks 2, and having perforation 3, through which the gas may pass lar apparatus,

as it ascends through the liquid. Attached to these perforated plates 3, are-bailies 3, on

the upper side, and 3*. on the'lower side.

The baffles retard the circulatorymotion of the liquid, induced by the rapidly rotating perforated disks 2. 4 is a shaft rotating in i the bearings 5; the disks 2, are suspended and rotated within the tank 1, whenethe shaft is driven by the pulley 6. 7 is a feed hopper by means of which the material to be treated is fed into the tank through the pipe 37. This pipe, preferably, passes through the sides of the tank soas to deliver the material to be treated below-the surface of the liquid, and in the vicinity of the rotating shaft. It is desirable to deliver the material to be treated close to the shaft. The.

rotary motion of the liquid in the immediate vicinity of the shaft will just about give the material the desired distribution. 8 is a pipe, preferably stationary, through which a1r or other gases may be delivered to the submerged rotating perforated disks 2, communicating with the source of gas supply through the pipe 9, and having a gas regulating valve 10. The gas, delivered into the liquid in' the tank through thesubmerged pipe 8, will, by it's own buoyancy ascend through the liquid and pass through the perforations in the disks and the plates. 11

1s an opening "in the bottom of the tank.

through which the gangue may be removed and wasted through the pipe 13. If desired, the material may be returnedto the tank for re-treatment through the pipes 12, 14, and .15, or passed on to a simifor further treatment, through the pipe 16. Air or other gas is introduced intothe pipe 14 through the pipe 17, ,thus making an. air lift of the pipe 14. Clogging in the opening 11, in the bottom of tank .1, is removed or prevented by an air orwater jet introduced through the pipe 18. 19 is alaunderinto which the mineral" froth 21 may overflow and be removed from the tank and delivered into the trough 20.

22 isa feed pipe for the fresh ore or material delivered into the hopper 7 to be introduced into the tank for treatment. 24 is a casing, preferably built in sections, sur rounding the disks and plates, and having bailies 23, around the inner surface.- The sections of'the casing may be bolted together by the rods 32, and these rods may also be used to lift the casing out of the tank when it becomesnecessary.

ing disks and to the plates, where it is pre The support for the casing and plates is preferably in the shape of a spider 28 having an opening in the center, 29, through which the gas issuing from the pipe 8 passes to the rotating. disks 2. The casing is preferably made in sections, both vertically and horizontally, to facilitate the assembling of the apparatus. It will be seen that by this arrangementof the casing a Space 26 is formed between the casing and the sides of the tank, in which the liquid is more quiescent than in the space within the casing, in which the disks rotate. This arrangement, allows the coarser ground ore to pass down through and between the plates and disks into the hopper 27, while the finer ore, or slimes, may pass through the more quiescent space 26 to the hopper 27. It-will be noticed that the plates 3 have lips 3 pro jecting downwardly at the bottom: this is to allowthe finely ground ore to pass over the plates and on the rotating disks near the shaft, to be worked toward the periphery, while the gas, issuing from the pipe 8, passesthrough the perforationsin the rotatvented from short-circuiting up through the middle by the lips 3 on the plates 3. The

perforations on the disks are arranged so that the gas passing through the disks will be delivered to the plates to be trapped by the lip 3*. For this reason there are prefer ably no perforations in the space toward the center of the disks. The projections 34 on the casings, are lugs through which pass bolts 32 to hold the plates in place. The up er section 30 of the casing may be made as igh or as low as desired to get the results sought-for. As the section 30 is made higher more material, or ore, being treated will pass throughxthe disks \and'plates' into the hopper 27 if the-casing 30 is made very low much of the coarser material will pass through the space 26 intothe hopper 27. The best height for each particular case can onlybeldetermined by'experimenting.

35 is a water pipe over the launder 19, by

'means of which jets of water wash the min-' eral froth from the overflow'launder 19 to thetrough 20 which conveys the froth away from the apparatus. 38 is an air pipe'having air jets arrangedso as to blow the froth mixed with suitable frothing agents.

toward the periphery of the tank. andinto the launder 19.

In operating the apparatus, the tank 1 filled with a liquid and the material to be treated; which may be assumed to be a floatableore pulp ground, say, to 80' mesh, and The say, several hundred or several thousand revolutions per minute, driven'by the pulley 6. The air, or gas, valvelO. isthen opened and the gas introduced into the tank 1 through the ipe 9and the statlonary pipe' 8, and its amount is regulated so as not to be in excess of that capable of passing through the perforations either in the disks 2 Or the plates 3. There is no mechanical connection between the rotating disks 2 and the stationary gas delivery pipe 8, so that the disks can conveniently be rotated at any speed desired.

The gas, in passing through the perforations of the rapidly rotatin disks, is atomized in contact with the liquid, and the atomized gas, in ascending through the liquid having the finely ground ore in-suspension, floats the mineral particles to the surface, as shown by 21, while the gangue passes downwardly into the hopper 27. The heavier particles of gangue pass downwardly within the casing and over and through the rotating disks, while the gangue slimes pass downwardly through the more quiescent space 26, between the casing and the tank.

The amount of separation. between the sands 'and the slimes with a constant supply of gas, depends largely on the height of the section, 30, and regulation may be controlled within fairly wide limits. In this way the apparatus may also act as a classifier, or pulp thickener, and once the most desirable gravity having been obtained by adjusting the height of the casing, this condition can always be maintained, no matter what the proportion of solid to liquid is on entering the tank. The sands and slimes, although the pipe-16. The mineral froth 21 rises to the surface and overflows into the launder- 19. It may be assisted toward the periphery of the tank by air jets from the pipe 38. The froth is broken up and washed out of the launder 19, by water jets from the pipe 35, placed directly over the launder.

It is intended to maintain a high rotary speedfor the disks, while the battles between the disks prevent the liquid from circulating from the disks to the plates becomes thoroughly atomized andin the best condition for flotation, and only a minimum amount of air is required, The atomizing effect will be confined to the spaces between the disksand plates, and the surface of the liquid will be fairly quiescent with only a moderate circulatory motion which tends to work the froth toward the periphery of the tank. The best number ofplates and'diskstouse for' each particular me can only be determined by experimenting: usually three will be sufiicient. a

The ore, or material to be treated, is pref- 115 with the disks. in this way, the gas, passing erably introduced through a pipe 37, submerged in the liquid, just below the froth. This leaves the surface entirely free and facilitates the removal of the froth from the liquid.. 1

The thickening of the pulp in the tank may be accomplished, either by the speed of rotation of the disks, the amount of gas introduced into the liquid, or the height of the casing above the disks. Usually all of these factors will be operative at the same time.

The perforations in the plates and disks are made somewhat larger than the size to which the ore is ground so that there will be no danger of the perforations becoming clogged, and experience has proved that they do not become clogged under the conditions.

The spider support for the casing and baiiies, as shown by 28, is a convenient arrangement. The pipe 8 delivers the gas to the disks, while the arms of the spider support the casing, and the space between the spider arms allows both the sands and the slimes to pass into the hopper27 The spider arms also act to retard the circulatory motion of the liquid in the'hopper below the disks.

ing downwardly around the periphery of the lower disk. This acts as a hood to confine the gas and give it an equal distribuforation, is distributed through a linear tio'n by forcing it to pass through the perquiescent as possible, although, of course,

some movement of the liquid is inevitable. A good'idea of the operation of the apparatus may be obtained from the following illustration: Suppose the disks rotate at a speed of 400 R. M. A perforation, say, 5nd inchin diameter, and 0.8 foot from the center, will travel a distance of 5 feet per revolution and a total distance of 2000 feet per minute. It is evident that the gas escaping, per minute, through the g znd 1I1Cl1 perdistance of 2000 feet of the liquid,if the liquid is stationary. If the liquid rotates,

with the disks it will be less. The maXi mum efficiency is obtained, therefore, by

having the relative motion between the disks and liquid as great as possible, and this condition is best realized in my apparatus when the liquid is as nearly stationary It is desirable to have a flange 2' project-- as possible, under the conditions. To best accomplish this, baflies are preferably interposed between the disks, and the disk mai-hined, or the surface of the disks other- This is wise made as smooth as possible.

i the preferred arrangement.

I claim:

1. In apparatus for separating minerals buoyancy passing it upwardly through the perforated disks and plates, and thus ,by atomizing the gas in contact with the liquid causing the fioatable material to rise to the surface of the liquid.

In apparatus for separating minerals from their gangue by flotation, a tank adapted to contain a liquid and the materialto be treated, a shaft rotatably mounted suspended within the tank, a plurality of perforated disks mounted on said shaft,

a plurality of perforated stationary plates interposed between the disks and alternating with them, means for rotating the shaft and disks, means for introducing a gas into the liquid in the tank and by its own buoyancy passing it-upwardly through the perforated disks'and plates, means for introducing the material to be treated into the tank to be acted upon by the atomized gas, and means for withdrawing the gangue from below the disks in the tank.

3. In apparatus for separating minerals from their gangue by flotation, a tank adapted to contain a liquid and the material to be treated, a plurality of perforated disks mounted on a vertical shaft, plates having bafiies interposed between the disks, means for introducing a gas into the liquid to be atomized in the liquid by the disks and plates, and means for rotating the disks.

4. In apparatus for separating minerals from their gangue by flotation, a plurality -of disks mounted on avertical shaft, platesand bafiies interposed between the disks, means for rotating the disks, and means for introducing a gas into the liquid in the tank to be atomized by alternately bringing it in contact with the disks and plates, and thus floating the'fioatable mineral particles 5. In apparatus for separating minerals from their gangue by flotation, a tank adapted to contain a liquid and the material to be treated, a plurality .of perforated disks mounted on a vertical shaft and suspended within the tank, perforated I plates interposed between the disks, means for, rotating the disks, means for introducing a gas into the liquid in'the tank to be atomized by the disks and plates, and means in connection with the disks and plates for preventingthe 5 short-circuiting of the gas in the vicinity of the shaft .in its ascent through the liquid.

6. In apparatus for separating minerals from their gangue by flotation, a tank adapted to contain a liquid and the material to be treated, means for introducing a gas into,

the tank and into the liquid from a submerged opening, a plurality of disks having means for atomizing the gas mounted on a vertical shaft suspended within the tank and submerged in the liquid, means for rotating the disks, and plates having means to retard the circulatory motion of the liquid induced by the rotating disks interposed between the disks.

7. In apparatus for separating minerals from their gangue by flotation, a tank adapt- 'ed=to contain a liquid and the material to A be treated, means for introducing a gas into the. tank andinto the liquid from a sub-.

2 5 merged opening to rise by itsown buoyancy, disks having means for. atomizing the gas mounted on a vertical shaft suspended Within the tank and submerged in-the liquid, means for rotating the disks, and means interposed between the disks for retarding the circulatory motion of the liquid induced by the rotating disks.

8. In apparatus for separating minerals,

motion of the liquid induced by the rotating atomizers.

9. In apparatus for separating minerals from their gangue by flotation, a tank adapted to. contain the liquid and the material to betreated, means for introducing a gas into the-tank andi into the liquid from a" sub.- merged opening to riseby its own buoyancy in the liquid, atomizers for the gas mounted on a vertical shaft suspended within the tank and submerged in the [1quid; nieans for ro'-' tating the atomizers, meansfiterposed between the atomizers fin retarding the circulatory motion of theliquid induced by the rotatmg atomizers, and a casingffiiterposed betvlgeen' the atomizers and the sides of the tan 60, 10. In apparatus for separating minerals p from their gangue" by flotation, a tank .from their gangue by flotation, a tank adapted to contain a liquid and the material to be treated, means ,for introducing a gas into the'tank and into the liquid from a submerged opening to rise by its own buoyancy in the liquid, atomizers for, the gas mounted on a vertical shaft suspended within the tank and submerged in the liquid, means for rotating the atomizers, means interposed between the atomizers'for retarding the circulatory motion of the liquid induced by the rotating atomizers, a hopper for the gangue located below the atomizers, and means for Withdrawing the gangue from the hopper.

11. In apparatus for gasifying a pulp, a tank adapted to contain the .pulp, means for introducing a gas into-the tank and into the pulpfrom a submerged opening to rise by its own buoyancy in the pulp", rotary means having perforations for atomizlng the gas in its ascent through the liquid, means for maintaining a relatively quiescent surface of the pulp, and means for creating a current of air over the relatively quiescent surface of the pulp toward the periphery of the tank.

12. In apparatus for separating minerals from their gangue by flotation, a tank adapted to contain a liquid, a shaft rotatabjy mounted suspended within the tank, ailuralityof perforated disks mounted on said shaft, a plurality of stationary plates interposed between the disks and alternating with them, and a casing surrounding the disks and supporting the plates, and means for, introducing a gas into the liquid in the tank and by its own buoyancy passing it upwardly through the rotating perforated disks and stationary plates. 4

13. In apparatusfor treating liquids with gases, a tank adapted to contain the liquid, a shaft ratatably mounted suspended within the tank, a plurality .of perforated disks mounted on said shaft, means. for retarding the circulatory motion of the liquid-'interposed'between the disks, a casing interposed between the disks and sides of the tank thus forming a relatively quiescent space be-' tween the casing and the tank, means for introducing a gas into the liquidin the tank to be acted upon by the rotating disks, and means for creating a current of air over the surface of the liquid toward the periphery of the tank.

14. In apparatusfor treating liquids with gases, a tank adapted to contain the liquid to be treated, a plurality of rotatably mounted parallel disks having means for subdividinga gas in theliquid, a plurality of stationary bafiies having means for sub-. dividing the resulting mixture of gas and liquid alternating with the disks, submerged means for injecting a gas into the and means for rotating the disks. 7 I

15. In apparatus for separating minerals liquid,

adapted to contain a liquid and the material to' be treated, means for introducing a gas into the liquid in the tank, andstationary and rotating surfaces having gas passages 1'30 arranged so that the gas in its ascent through the liquid will alternately pass atomized by the rotating disks, and means interposed between the disks for retarding the circulatory motion of the liquid induced by the rotating disks.

17. In apparatus for separating minerals.

from their gangue by flotation, a tank adapted to contain a liquid and the material to be treated, a plurality of atomizers having gas passages suspended within the tank and submerged in the liquid, means for causing a flow of gas through the gas passages of'the atomizers, means for rotating the atomizers about a central axis, and means interposed between the atomizers for retarding the circulatory motion of the liquid inducedby the rotating atomizers.

18. In apparatus for treating liquids with gases, a tank adapted tocontain the liquid to be treated, a plurality of perforated disks arranged with a space between them mounted on a shaftwithin the tank submerged, means for injecting a gas into the liquid, means for rotating the disks, and means for effecting an intimate mixture between the gas and the liquid. e a 19. In apparatus for treating liquids wit gases, a tank adapted to contain the liquid to be treated, a plurality of rotatably.

mounted perforated disks suspended within the tank, a plurality of stationary perforated baflles alternating with the disks submerged, means for injecting a gas into the liquid, and means for rotating the disks.

20. In apparatus for treating liquids with gases, a tank adapted to contain a liquid, a

stationary casing within the tank having a gas inlet and a gas outlet and a liquid inlet and a liquid outlet communicating with the liquid in the tank, a rotary shaft within said casing, a series of rotary members mounted on said shaft, and a series of stationary members interposed between the rotary members;

- WILLIAM E. GREENAWALT. Witnesses:

IVA L. MYERS, F ED L. Soor'r. 

